This invention relates to a damper device and, especially to a buffering assembly used in a hinge structure of a lid or cover, such as a stool lid of a toilet stool of Western style or a cover of a personal computer of wrap-top type which is opened upwards and closed downwards.
Such manually operated lid or cover which is hinged about a horizontal axis can be opened lightly if the frictional resistance between an axle and a bearing of the hinge structure is small. However, if it is released from a hand when it is closed, it freely runs down against a body to cause not only an unpleasant strike sound but also a possible damage of the device due to shock. However, if the frictional resistance is increased for preventing these problems, unnecessary resistance acts at the time of opening and the hand must be used to the last at the time of closing. In order to avoid such troubles, it has been proposed, as described, for example, in the Japanese utility model opening gazette No. H2-6594, to use a buffering fluid such as grease for braking the lid therewith when it is closed. However, such a device as using a fluid is complicated in structure and, moreover, it conceives such problems in that it is troublesome to handle the fluid in the manufacturing process and it may leak out in the future. With this structure, moreover, a long time is needed for closure when only the gravity regards, since a uniform braking torque acts throughout the closing operation.
Accordingly, an object of this invention is to provide a novel and improved damper device using no buffering fluid, in which the braking effect does not appear at the time of opening but appears only at the time of closing.
Another object of this invention is to provide an improved damper device for a hinge structure in which the braking effect at the time of closing is raised especially at the last step to prevent collision of the lid.
A further object of this invention is to provide an improved damper device in which the braking effect is raised especially within a specific range in the way of closing, so that the lid can be stood still at any position within the range.